Hempcrete is a new product that has a lot of potential. It is a mixture of hemp hurds (also called shives) and lime. it is a material for construction and insulation. It is easier to work with that the traditional lime plasters and is an insulator and a moisture regulator. It lacks the brittleness of concrete but it has a compressive strength of 1MPa a twentieth of concrete. This means that hempcrete walls cannot be free formed but need to be framed to help with compressive forces.
Hemp absorbs a lot of CO2, it can absorb as much as 165kg of carbon per 1 m 3.
The first hemp farms are just starting in the usa in 2013 so hopefully will be commercially available soon.